"Bra Party" can be used to identify a band or a song that is usually heavy metal, rock, metal, or hard rock. comes from pictures of girls at my school having a party half naked that everyone found. It started as describing a song as "hard" then someone said "like my dick" and someone else interjected "after looking at the bra party pics!" so bra party was invented

Person 1: System of a Down is pretty hard!
Person2: Definitely, they are a Bra Party band